.300 BLK Reloading Woes

[AJC1]

I’m using 1680 and 190 gr Sub-X

1680 and lil gun seem to be major players

 

[n2omike]

I load the 300BO subsonic with a 10.5" barrel and Berrys 220 grain bullets. I went through a lot of different powders looking for one that was both quiet, accurate and gave consistent velocities. There was a wide range of results. I can't recall offhand what worked the best for me. Will have to look through my notes, but it was a fun test.

I do not crimp 300BO. Only neck expanding and de-burring. The Berrys are nice, as no case flaring/crimping is required... saving steps over cast/coated bullets. Now if RMR would make a good subsonic expanding 300BO bullet, we'd really be in business!

As I recall, 4227 was one of my top performers with the Berrys 220 grain plated bullets. The length of the gas system is a big factor. The faster, less gassy (quieter) powders work best with the pistol length gas systems. Mine has a 10.5" barrel and cycles fine with about any powder. Louder, more gassy/slower powders are often required with the longer carbine/rifle gas systems.

I tested Lil Gun, Enforcer, H110, N120, and maybe something else. Settled on 4227. Delivered the best accuracy and consistent velocities over the chrono. Definitely worth testing if you like subsonic 220 grain.

 

[thump_rrr]

Another thing to watch out for is the neck thickness. Some brass is thicker so after forming you end up with the neck wall thickness too thick. I ended doing a bunch of brass sorting due to it. My Ruger Ranch rifle seems to handle it all, but my AR's don't.

This is the most likely problem.
The minute you said you formed your own brass this came to mind.

 

[n2omike]

This is the most likely problem.
The minute you said you formed your own brass this came to mind.

I bought some 300BO brass that was made from LC 5.56 and it worked fine. Wouldn't want to go through the hassle/troubleshooting of doing it myself. Last batch came from Starline... and is likely where the next will come from as well. I like supporting Starline. It's also the 'easy button'... as you know it's good to go right out of the bag.

If I was retired, had time to burn and actually wanted the challenge... sure, it might be fun to roll my own brass... but I'm not. Lol. Respect to those who do.

Right now, I'm stockpiling some things for when I am retired... assuming this stuff is even legal by then. Lol

 

[Lennyjoe]

Built my BO when it was still a new caliber so I made my own brass out of LC brass. Still have several hundred made and unused brass cases.

 

[GravelRider]

This is the most likely problem.
The minute you said you formed your own brass this came to mind.

I sorted the brass based upon the list on the 300BLK forum. This had no bearing on the problem, fortunately. It turned out to be too long of COAL, and overcrimping.

 

[GravelRider]

I bought some 300BO brass that was made from LC 5.56 and it worked fine. Wouldn't want to go through the hassle/troubleshooting of doing it myself. Last batch came from Starline... and is likely where the next will come from as well. I like supporting Starline. It's also the 'easy button'... as you know it's good to go right out of the bag.

If I was retired, had time to burn and actually wanted the challenge... sure, it might be fun to roll my own brass... but I'm not. Lol. Respect to those who do.

Right now, I'm stockpiling some things for when I am retired... assuming this stuff is even legal by then. Lol

This was the first time I ever formed my own brass out of another cartridge, and it was a fun challenge. This being said, I'm not retired either, and I started this process about a year ago. Lol. I'm glad I did it though. Besides the 300 BLK brass being very expensive, I enjoyed the process, and learned something along the way.

 

[n2omike]

This was the first time I ever formed my own brass out of another cartridge, and it was a fun challenge. This being said, I'm not retired either, and I started this process about a year ago. Lol. I'm glad I did it though. Besides the 300 BLK brass being very expensive, I enjoyed the process, and learned something along the way.

It's around $0.27 to $0.30 each from Starline, which isn't that bad, considering you can just dump them out of the bag and go. Not sure what a person has to pay for once fired LC 5.56 casings... if you're not using a current stockpile.

But, I'm looking forward to playing some more with the caliber. Not bad for basically a pistol sized cartridge that performs close to a 30-30 and fits a semi-auto AR platform.

 

[jmorris]

Not sure what a person has to pay for once fired LC 5.56 casings...

I have never bought spent .223 brass. I have always gotten more than I need from 3 gun matches.

The business I made a brass cutting machine to convert 5.56 to 300blk bought from .gov auctions, generally at just under scrap prices but you have to haul it yourself.

 

[GravelRider]

I went out and fired 20 test rounds today. Problem was that I did it in a snow storm. The snow had nearly stopped when I left, but picked up again once I got to the range. My chronograph readings were all over the place, from mid-900s to 1900 fps. On subsonics. Lol. The standard deviation was over 300 fps.

Good news was that they reliably cycled the action every shot, and accuracy was good.

I'll make a few more tonight, and chrono them in clear weather.

 

[GravelRider]

I got 50 good test rounds banged out, and seven that wouldn't fit in the case gauge (barely), but seemed to chamber fine. I separated these, and will see how they actually fire compared to the rest.

 

[AJC1]

I went out and fired 20 test rounds today. Problem was that I did it in a snow storm. The snow had nearly stopped when I left, but picked up again once I got to the range. My chronograph readings were all over the place, from mid-900s to 1900 fps. On subsonics. Lol. The standard deviation was over 300 fps.

Good news was that they reliably cycled the action every shot, and accuracy was good.

I'll make a few more tonight, and chrono them in clear weather.

Are you going to find that brass in the spring or did you gopher it out of the snow

 

[GravelRider]

Are you going to find that brass in the spring or did you gopher it out of the snow

It was an icy snowy mix, so there was a hard crust on top that the brass stuck to. It was actually MUCH easier to pick up than usual. Easy to see, and most were sticking up and easy to grab.

 

[Blue68f100]

I got 50 good test rounds banged out, and seven that wouldn't fit in the case gauge (barely), but seemed to chamber fine. I separated these, and will see how they actually fire compared to the rest.

View attachment 1121248

For those that barely fit the gauge, see it it the base. Inserting the base end into the gauge and see if binds. An extractor mark can cause this. If it binds just push and give it a twist normally fixed it to drop in freely.

 

[GravelRider]

For those that barely fit the gauge, see it it the base. Inserting the base end into the gauge and see if binds. An extractor mark can cause this. If it binds just push and give it a twist normally fixed it to drop in freely.

The base seems good. It looks like it's binding at the necks. But, I can push them into the gauge to fit. I don't think they'll be an issue with my gun, but we'll see. The headstamps that aren't fitting are mixed, and are the same as ones that do fit.